|Número de publicación||US5569950 A|
|Tipo de publicación||Concesión|
|Número de solicitud||US 08/563,510|
|Fecha de publicación||29 Oct 1996|
|Fecha de presentación||28 Nov 1995|
|Fecha de prioridad||16 Ago 1994|
|Número de publicación||08563510, 563510, US 5569950 A, US 5569950A, US-A-5569950, US5569950 A, US5569950A|
|Inventores||David A. Lewis, Chandrasekhar Narayan|
|Cesionario original||International Business Machines Corporation|
|Exportar cita||BiBTeX, EndNote, RefMan|
|Citas de patentes (11), Otras citas (4), Citada por (85), Clasificaciones (20), Eventos legales (5)|
|Enlaces externos: USPTO, Cesión de USPTO, Espacenet|
This is a continuation of application Ser. No. 08/291,222 filed on Aug. 16, 1994, now abandoned.
1. Field of the Invention
The present invention relates generally to electronic chip cooling devices and more particularly to a device which will provide active cooling to reduce temperature excursions of electronic chips, which will limit thermal fatigue, increase product life cycle, allow for larger chips and permit chips to be directly attached to substrates with unmatched coefficients of thermal expansion with less reliability concerns.
2. Discussion of the Prior Art
In today's high power PC's and workstations, the number of on/off cycles is limited due to fatigue in the solder interconnections and device wiring because of the high operating temperature of the chip as a result of the high power dissipation. Conventional passive cooling is limited since it relies on a temperature difference between the chip and ambient which is cooled by a fan. Thus, the operating temperature is high, resulting in large temperature excursions between the on and off states. As a consequence of these large temperature excursions that the chips are subjected to, the size of the chip is limited to allow for the required on/off cycles.
In the more recent environmental PC's, power management techniques are being used to conserve power by monitoring system activity and reducing power levels in parts of the system. Thermal cycling is potentially a major concern, since each inactive mode will allow time for the chip to cool. The typical cycling of an environmental PC is represented by curve 1 in FIG. 1, where the normal operating temperature is arbitrarily indicated as 80° C. and the temperature during a sleep cycle is reduced to 70° C. Curve 1 shows that the cycling of such a machine will have a frequency of the order of a few seconds as opposed to the frequency of a normal on/off cycle which is typically one day. Assuming a two second cycle time, on average, this translates to about 15,000 cycles per 8 hour day, with a 10° C. swing. This compares to a total specification of 20,000 on/off cycles for the lifetime of a machine (with a temperature swing of 50° C.). These "mini" cycles can add up to 4 million cycles a year and can pose a serious reliability problem.
Thus, there is a need for a method or structure that can limit either the number of thermal cycles and/or the temperature swings to enhance the product reliability.
The present invention is directed to the use of a thermal electric cooling (TEC) device in cooperation with a thin film thermocouple to provide active temperature control for an electronic chip to enhance reliability and extend service life. The electronic chip cooling device of the present invention includes attaching the cold side of the TEC device to the electronic chip and attaching a heat sink means to the hot side of the TEC device. A temperature sensing means such as a thermocouple is attached between the TEC device and the chip for sensing the temperature of the chip. A voltage source is coupled to the TEC device and a feedback control circuit means is coupled between the thermocouple and the voltage source. The feedback control circuit controls the level of voltage supplied to the TEC device in response to the temperature of the chip, to maintain the chip at the desired substantially constant temperature.
In the case of systems which have inactive modes of operation such as those proposed for environmental PC's to conserve power, the temperature of the chip can be controlled by the device of the present invention to limit both the number and magnitude of thermal excursions experienced by the chip during operation. For conventional chips, the operating temperature of the chip can be significantly lowered to extend the permissible on-off cycles. Furthermore, the present invention can permit chips to be cooled to a sufficiently low temperature to allow larger chips with a greater distance to neutral point than is currently possible. The present invention also permits chips to be directly attached to the cards even though the coefficient of thermal expansion of the chips to cards are not matched.
FIG. 1 is a graph having three different time versus temperature curves to compare excursions for prior art cooling devices (curve 1) with cooling provided by the device of the present invention (curves 2 and 3).
FIG. 2 is a cross-sectional schematic depiction of the electronic chip cooling device of the present invention. FIGS. 3 shows a clock voltage pulse train.
Referring now to FIG. 2, the present invention is directed to an electronic chip cooling device 10 for actively controlling the temperature of a chip. As shown in FIG. 2, electronic chip 12 is attached to substrate 14 by, for example, solder balls 16. A thermal electric cooling device 18 is secured to the exposed surface of chip 12 by the use of any thermally conductive adhesive material. The TEC device 18 is secured to the chip 12 such that the cold side 20 of the device 18 is secured to chip 12. A temperature sensing means such as thin film thermocouple 22 is attached between the cold side 20 of TEC device 18 and chip 12. The temperature sensing means may alternatively be built into the chip or the electronic package adjacent to the interconnection between the TEC device 18 and the chip 12. Heat sink 24 is secured to the hot side 26 of TEC device 18. An output 28 of the thermocouple 22 is coupled to a feedback control circuit 30. The control circuit 30 is coupled to a voltage source 32 which is coupled to an input 34 to the TEC device 18. The input 34 provides a voltage potential between the hot and cold sides of the TEC device 18. Both the control circuit 30 and voltage source 32 may be circuitry that is built into the chip or electronic package or separate extrinsic circuits.
As is well known, a TEC device is comprised of a bimetallic strip that operates under the Peltier effect. The cool side 20 of the TEC device 18 is thermally anchored to the chip 12 and the hot side 26 is sufficiently cooled with the heat sink 24. A voltage potential is applied between the hot and cold sides of the strip and the difference in temperature between the hot and cold sides is directly proportional to the voltage applied to the device.
In operation, the temperature sensing means 22 senses the temperature of the chip 12 and a signal representative of that temperature is coupled to the control circuit 30. The feedback control circuit 30 controls the level of voltage supplied by the voltage source 32 in response to the temperature of the chip. The feedback control circuit 30 is designed to maintain a substantially constant set point temperature by continually adjusting the voltage potential to the TEC device 18 so that the temperature difference between the hot and cold sides 26, 20 remains substantially constant. Control circuits for this purpose are well known and therefore it is not necessary to provide a description thereof.
The temperature of the chip 12 is actively controlled by the thin film thermocouple 22 being placed adjacent to the chip 12 and being coupled to the feedback control circuit loop to efficiently monitor and control the temperature of the chip to a desired value in real time with a short response time. For example, if the temperature of the chip 12 rises, the thermocouple 22 senses the rise and the control circuit 30 signals the voltage source 32 to apply a voltage to the TEC device 18 to reduce the temperature of the cool side 20 in order to cool the chip 12 back down to the desired temperature. The heat removed from the chip 12 is transferred to the hot side 26 of the TEC device 18 and dissipated through the heat sink 24. Thus, the device 10 of the present invention controls the temperature of the chip to limit both the number and magnitude of thermal excursions experienced by the chip during operation. Curve 2 of FIG. 1 is a time versus temperature plot of the thermal excursions of a chip cooled using the device 10 of the present invention. It can be seen from curve 2 that the temperature of the chip is maintained substantially at 70° C. The temperature changes are much less frequent and of a much less amplitude.
The size and efficiency of the heat sink 24 must also allow for the additional power dissipated by the TEC device 18. As the temperature of the heat sink 24 increases, it becomes more efficient. Using the TEC device 18, the heat sink 24 is decoupled from the temperature of the chip 12. The response time of a heat sink, when attached to a chip, is too slow to allow the effective control of chip temperature. With the present invention, by decoupling the chip temperature from the heat sink temperature, the slow response time can be overcome by the fast response time of the TEC device. A multiple fin metallic heat sink is typical but any configuration or form of heat sink may be used. The power dissipated by the TEC device 18 will be approximately twice the power that is extracted from chip. This additional power consumption can be compensated for by using a larger heat sink or a higher speed fan. This will result in a slightly higher package temperature, but much lower and more uniform chip temperature. In addition, the feedback control circuit 30 can be also coupled to a variable speed fan to provide additional cooling in response to the temperature of the chip.
Furthermore, the device of the present invention can be utilized to provide a substantially lower chip operating temperature to extend the life of the chip. For example, the operating temperature of the chip as depicted by curve 3 of FIG. 1, can be reduced to approximately 35° C. At such a significantly lower temperature, it is possible to permit larger chips to be used than is currently allowable. In addition, actively controlling the temperature of the chip will allow chips to be directly attached to cards even where the coefficient of thermal expansion is not matched.
Thus, the present invention not only provides a device for limiting the operating temperature of a chip, but also to actively control the operating temperature to any desired temperature. The device of the present invention limits temperature excursions of a chip due to power management related inactive cycles. The present invention permits chips to be directly attached to cards even though the coefficient of thermal expansion is not matched. In addition, the present invention provides for the ability to use larger chips in existing configurations without compromising chip service life.
In another embodiment, the structure of the present invention does not require extrinsic temperature and control circuits. For example, the voltage to the TEC device can be preprogrammed to specific values, based on the mode of chip usage or level of activity at that moment. When the chip is in "normal" mode, the control circuit will adjust the voltage to a preset suitable value; when the chip is in sleep mode, the voltage will be adjusted to another preset value sufficient to maintain the desired chip temperature. This simplifies the control circuit configuration as no feedback circuit is required.
In a further embodiment, the device of the invention utilizes the clock pulse, a voltage driven off the clock signal, or other similar built-in pulsed voltage to drive the TEC device. Total power to the TEC device is controlled by switching the clock signal on and off during pulses depending on the output from the thermocouple or other control system, including a preprogrammed control. FIG. 3 shows a clock voltage pulse train and a corresponding pulse train taken from the clock pulse with the pulses modified for normal, off and intermediate modes.
While the invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.
|Patente citada||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US4685081 *||17 Dic 1984||4 Ago 1987||Allied Corporation||Peltier junction used for thermal control of solid state devices|
|US4704872 *||25 Nov 1986||10 Nov 1987||The United States Of America As Represented By The Secretary Of The Air Force||Thermally controlled T/R module test apparatus|
|US5028988 *||27 Dic 1989||2 Jul 1991||Ncr Corporation||Method and apparatus for low temperature integrated circuit chip testing and operation|
|US5032897 *||28 Feb 1990||16 Jul 1991||International Business Machines Corp.||Integrated thermoelectric cooling|
|US5065085 *||31 Oct 1989||12 Nov 1991||Strachan-Aspden Limited||Thermoelectric energy conversion|
|US5079618 *||2 Jul 1991||7 Ene 1992||Micron Technology, Inc.||Semiconductor device structures cooled by Peltier junctions and electrical interconnect assemblies|
|JPH05326824A *||Título no disponible|
|JPS6272148A *||Título no disponible|
|JPS61253842A *||Título no disponible|
|JPS63224383A *||Título no disponible|
|JPS63265484A *||Título no disponible|
|1||No Author, "Thermoelectric Temperature Cycler For Chip Functional Testing," Research Disclosure, Mar. 1989, No. 299.|
|2||*||No Author, Thermoelectric Temperature Cycler For Chip Functional Testing, Research Disclosure , Mar. 1989, No. 299.|
|3||Skobern, "Thermoelectrically Cooled Module," IBM Technical Disclosure Bulletin, vol. 27, No. 1A, Jun. 1984, p. 30.|
|4||*||Skobern, Thermoelectrically Cooled Module, IBM Technical Disclosure Bulletin, vol. 27, No. 1A, Jun. 1984, p. 30.|
|Patente citante||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US5831333 *||14 May 1996||3 Nov 1998||Sun Microsystems, Inc.||Integrated junction temperature sensor/package design and method of implementing same|
|US5931000 *||23 Abr 1998||3 Ago 1999||Turner; William Evans||Cooled electrical system for use downhole|
|US6052559 *||2 May 1997||18 Abr 2000||Motorola, Inc.||Thermoelectrically cooled low noise amplifier and method|
|US6058012 *||27 Abr 1998||2 May 2000||Compaq Computer Corporation||Apparatus, method and system for thermal management of an electronic system having semiconductor devices|
|US6134892 *||3 Feb 1999||24 Oct 2000||Aps Technology, Inc.||Cooled electrical system for use downhole|
|US6147868 *||5 Mar 1999||14 Nov 2000||Schneider Electric Sa||Electronic power components module|
|US6196002||24 Jun 1999||6 Mar 2001||Advanced Micro Devices, Inc.||Ball grid array package having thermoelectric cooler|
|US6206267 *||30 Dic 1999||27 Mar 2001||3Com Corporation||Full coverage thermal couple|
|US6265820||27 Ene 1999||24 Jul 2001||Emagin Corporation||Heat removal system for use in organic light emitting diode displays having high brightness|
|US6363315 *||13 Jul 2000||26 Mar 2002||Caterpillar Inc.||Apparatus and method for protecting engine electronic circuitry from thermal damage|
|US6389225||14 Jul 1999||14 May 2002||Delta Design, Inc.||Apparatus, method and system of liquid-based, wide range, fast response temperature control of electronic device|
|US6408215 *||22 Abr 1998||18 Jun 2002||Agilent Technologies, Inc.||Isothermal port for microwave network analyzer and method|
|US6410971||29 Nov 2001||25 Jun 2002||Ferrotec (Usa) Corporation||Thermoelectric module with thin film substrates|
|US6424533||29 Jun 2000||23 Jul 2002||International Business Machines Corporation||Thermoelectric-enhanced heat spreader for heat generating component of an electronic device|
|US6463396||19 Abr 1999||8 Oct 2002||Kabushiki Kaisha Toshiba||Apparatus for controlling internal heat generating circuit|
|US6476627||21 Oct 1996||5 Nov 2002||Delta Design, Inc.||Method and apparatus for temperature control of a device during testing|
|US6487463||8 Jun 1998||26 Nov 2002||Gateway, Inc.||Active cooling system for an electronic device|
|US6489793||14 Jul 1999||3 Dic 2002||Delta Design, Inc.||Temperature control of electronic devices using power following feedback|
|US6518782||29 Ago 2000||11 Feb 2003||Delta Design, Inc.||Active power monitoring using externally located current sensors|
|US6525934 *||29 Mar 2000||25 Feb 2003||International Business Machines Corporation||Thermal controller for computer, thermal control method for computer and computer equipped with thermal controller|
|US6549026 *||14 Jul 2000||15 Abr 2003||Delta Design, Inc.||Apparatus and method for temperature control of IC device during test|
|US6621361||17 Oct 2000||16 Sep 2003||Cts Corporation||Dual oven oscillator using a thermoelectric module|
|US6650132||19 Jul 2002||18 Nov 2003||Delta Design, Inc.||Method and apparatus for temperature control of a device during testing|
|US6788084||5 Sep 2002||7 Sep 2004||Delta Design, Inc.||Temperature control of electronic devices using power following feedback|
|US6862405||21 Ago 2002||1 Mar 2005||Delta Design, Inc.||Apparatus, method and system of liquid-based, wide range, fast response temperature control of electric devices|
|US6962437 *||16 Dic 1999||8 Nov 2005||Lsi Logic Corporation||Method and apparatus for thermal profiling of flip-chip packages|
|US7029951||12 Sep 2003||18 Abr 2006||International Business Machines Corporation||Cooling system for a semiconductor device and method of fabricating same|
|US7064036||1 Sep 2004||20 Jun 2006||Micron Technology, Inc.||Dual-gate transistor device and method of forming a dual-gate transistor device|
|US7148589||20 Ene 2004||12 Dic 2006||Kabushiki Kaisha Toshiba||Method and apparatus for controlling internal heat generating circuit|
|US7185500||28 Nov 2003||6 Mar 2007||Active Cool Research And Development Ltd||Active cooling system for CPU|
|US7268019||22 Sep 2004||11 Sep 2007||Halliburton Energy Services, Inc.||Method and apparatus for high temperature operation of electronics|
|US7276814||29 Jun 2005||2 Oct 2007||Ruggedcom Inc.||Environmentally hardened ethernet switch|
|US7508671 *||10 Oct 2003||24 Mar 2009||Intel Corporation||Computer system having controlled cooling|
|US7609518 *||27 Oct 2009||Iceotope Limited||Cooling computer components|
|US7633752 *||15 Dic 2009||Intel Corporation||Cooling an integrated circuit die with coolant flow in a microchannel and a thin film thermoelectric cooling device in the microchannel|
|US7957137||7 Jun 2011||Intel Corporation||Method for cooling an integrated circuit die with coolant flow in a microchannel and a thin film thermoelectric cooling device in the microchannel|
|US8209989 *||3 Jul 2012||Intel Corporation||Microarchitecture control for thermoelectric cooling|
|US8547687||1 Oct 2009||1 Oct 2013||Koninklijke Philips N.V.||Power semiconductor device adaptive cooling assembly|
|US8586982||25 Ago 2010||19 Nov 2013||International Business Machines Corporation||Semiconductor test chip device to mimic field thermal mini-cycles to assess reliability|
|US8803275 *||12 Mar 2008||12 Ago 2014||Toyota Jidosha Kabushiki Kaisha||Semiconductor device including power semiconductor element, branch line, and thermoelectric conversion element, and electrically powered vehicle|
|US8845880||21 Dic 2011||30 Sep 2014||Genia Technologies, Inc.||Nanopore-based single DNA molecule characterization, identification and isolation using speed bumps|
|US8889348||7 Jun 2007||18 Nov 2014||The Trustees Of Columbia University In The City Of New York||DNA sequencing by nanopore using modified nucleotides|
|US8962242||12 Oct 2011||24 Feb 2015||Genia Technologies, Inc.||System for detecting electrical properties of a molecular complex|
|US8986629||26 Feb 2013||24 Mar 2015||Genia Technologies, Inc.||Sensor circuit for controlling, detecting, and measuring a molecular complex|
|US9041420||13 May 2013||26 May 2015||Genia Technologies, Inc.||Systems and methods for characterizing a molecule|
|US9047060 *||16 Ago 2013||2 Jun 2015||Adlink Technology Inc.||Heating element and circuit module stack structure|
|US9110478||18 Oct 2011||18 Ago 2015||Genia Technologies, Inc.||Temperature regulation of measurement arrays|
|US9121059||21 Dic 2011||1 Sep 2015||Genia Technologies, Inc.||Nanopore-based single molecule characterization|
|US9228763 *||3 Dic 2012||5 Ene 2016||Samsung Electronics Co., Ltd.||Thermoelectric cooling packages and thermal management methods thereof|
|US9322062||22 Oct 2014||26 Abr 2016||Genia Technologies, Inc.||Process for biosensor well formation|
|US9326423||2 Ago 2013||26 Abr 2016||Commissariat A L'energie Atomique Et Aux Energies Alternatives||Method for limiting the variation in the temperature of an electrical component|
|US20030135601 *||30 Dic 2002||17 Jul 2003||Pozzuoli Marzio Paride||Environmentally hardened ethernet switch|
|US20040150933 *||20 Ene 2004||5 Ago 2004||Nobutaka Nishigaki||Method and apparatus for controlling internal heat generating circuit|
|US20050026528 *||29 Jul 2003||3 Feb 2005||Forsten Herman Hans||Fire resistant fabric composite, process for fire-blocking a mattress and mattress set, and a mattress and mattress set fire-blocked thereby|
|US20050059238 *||12 Sep 2003||17 Mar 2005||International Business Machines Corporation||Cooling system for a semiconductor device and method of fabricating same|
|US20050078451 *||10 Oct 2003||14 Abr 2005||Ioan Sauciuc||Computer system having controlled cooling|
|US20050146850 *||28 Nov 2003||7 Jul 2005||Ronen Meir||Active cooling system for cpu|
|US20050213301 *||29 Mar 2004||29 Sep 2005||Ravi Prasher||Cooling an integrated circuit die with coolant flow in a microchannel and a thin film thermoelectric cooling device in the microchannel|
|US20060007614 *||29 Jun 2005||12 Ene 2006||Ruggedcom Inc.||Environmentally hardened ethernet switch|
|US20060060964 *||22 Sep 2004||23 Mar 2006||Christopher Golla||Method and apparatus for high temperature operation of electronics|
|US20070109742 *||16 Nov 2006||17 May 2007||Hopton Peter J||Cooling computer components|
|US20070296434 *||24 Oct 2006||27 Dic 2007||Fujitsu Limited||Temperature control method and apparatus and test method and apparatus of semiconductor devices|
|US20080236175 *||30 Mar 2007||2 Oct 2008||Pedro Chaparro Monferrer||Microarchitecture control for thermoelectric cooling|
|US20100046167 *||2 Nov 2009||25 Feb 2010||Ravi Prasher||Cooling an integrated circuit die with coolant flow in a microchannel and a thin film thermoelectric cooling device in the microchannel|
|US20100101878 *||12 Mar 2008||29 Abr 2010||Toyota Jidosha Kabushiki Kaisha||Semiconductor device and electrically powered vehicle|
|US20110192723 *||11 Ago 2011||Genia Technologies, Inc.||Systems and methods for manipulating a molecule in a nanopore|
|US20110193249 *||8 Feb 2010||11 Ago 2011||Genia Technologies, Inc.||Systems and methods for forming a nanopore in a lipid bilayer|
|US20130139524 *||6 Jun 2013||Jae Choon Kim||Thermoelectric cooling packages and thermal management methods thereof|
|US20140103947 *||14 Mar 2013||17 Abr 2014||Huy N. PHAN||Thermal reliability testing systems with thermal cycling and multidimensional heat transfer|
|US20150048073 *||16 Ago 2013||19 Feb 2015||Adlink Technology Inc.||Heating element and circuit module stack structure|
|CN101421841B||20 Feb 2007||30 Mar 2011||格罗方德半导体公司||A circuit lid with a thermocouple|
|CN102171817B||1 Oct 2009||12 Feb 2014||皇家飞利浦电子股份有限公司||Power semiconductor device adaptive cooling assembly|
|DE10104219A1 *||31 Ene 2001||22 Ago 2002||Infineon Technologies Ag||Active cooling device for semiconductor module has cooling provided by thermoelectric active cooling layer regulated by measured temperature of semiconductor module|
|DE10104219B4 *||31 Ene 2001||24 May 2006||Infineon Technologies Ag||Anordnung zur aktiven Kühlung eines Halbleiterbausteins und Verfahren zum Betrieb der Anordnung|
|DE112007000478B4 *||20 Feb 2007||9 Jun 2011||Globalfoundries Inc.||Intergrierte Schaltung mit einem Thermoelement|
|EP1369915A2 *||4 Abr 2003||10 Dic 2003||Heraeus Sensor-Nite GmbH||Semiconductor device with integrated circuit, heat sink and temperature sensor|
|EP2175484A1 *||7 Oct 2008||14 Abr 2010||Philips Electronics N.V.||Power semiconductor device adaptive cooling assembly|
|EP2693140A1||25 Jul 2013||5 Feb 2014||Commissariat à l'Énergie Atomique et aux Énergies Alternatives||Method for limiting the temperature variations of an electric component|
|WO2000004582A1 *||14 Jul 1999||27 Ene 2000||Schlumberger Technologies, Inc.||Temperature control of electronic devices using power following feedback|
|WO2003046702A2 *||28 Nov 2002||5 Jun 2003||Active Cool Ltd.||Active cooling system for cpu|
|WO2003046702A3 *||28 Nov 2002||29 Ene 2004||Active Cool Ltd||Active cooling system for cpu|
|WO2004011861A1 *||28 Jul 2003||5 Feb 2004||Bookham Technology Plc||Thermoelectric cooler drive control|
|WO2007098219A2 *||20 Feb 2007||30 Ago 2007||Advanced Micro Devices, Inc.||A circuit lid with a thermocouple|
|WO2007098219A3 *||20 Feb 2007||13 Mar 2008||Advanced Micro Devices Inc||A circuit lid with a thermocouple|
|WO2010041175A1 *||1 Oct 2009||15 Abr 2010||Koninklijke Philips Electronics N.V.||Power semiconductor device adaptive cooling assembly|
|Clasificación de EE.UU.||257/467, 257/E23.08, 257/930, 257/E23.082, 361/688, 257/469, 361/719, 257/713, 257/712, 361/718, 361/717|
|Clasificación internacional||H01L23/38, H05K7/20, H01L23/34|
|Clasificación cooperativa||Y10S257/93, H01L23/34, H01L2924/0002, H01L23/38|
|Clasificación europea||H01L23/38, H01L23/34|
|5 Ene 2000||FPAY||Fee payment|
Year of fee payment: 4
|20 Ene 2004||FPAY||Fee payment|
Year of fee payment: 8
|5 May 2008||REMI||Maintenance fee reminder mailed|
|29 Oct 2008||LAPS||Lapse for failure to pay maintenance fees|
|16 Dic 2008||FP||Expired due to failure to pay maintenance fee|
Effective date: 20081029